This invention is concerned with improvements in or relating to shoe upper conforming machines, more especially so-called pulling over and toe lasting machines, that is machines in the operation of which a shoe upper can be tensioned (pulled) over a form (last) by the application of pulling grippers in the toe and forepart regions of the upper and thereafter the marginal portions of the upper (lasting margin) in the region of the toe and forepart are secured against appropriate surface areas of an insole held against the bottom of the form (last).
The word "shoe" where used herein is to be understood as referring to outer footwear generally and as including an article of outer footwear in the course of its manufacture.
There is hereinafter described in detail, to illustrate the invention by way of example, a so-called pulling over and toe lasting machine (hereinafter called the "illustrative machine"), this illustrative machine comprising a support by which a form, constituted by a last on which a shoe upper is to be conformed, can be supported, bottom down, with an insole held against the bottom thereof, gripper means, comprising a plurality of grippers spaced apart in relation to said support so as to enable marginal portions of the forepart of a shoe upper carried on a last supported by said support to be gripped, and means for effectiving relative movement between said support and the gripper means whereby, with marginal portions of a forepart of an upper gripped as aforesaid, such upper can be tensioned over its last. For operating the grippers to grip an upper marginal portion as aforesaid, each gripper has gripper actuating means, in the form of a solenoid valve-controlled pneumatic piston-and-cylinder arrangement, associated therewith. Furthermore, for effecting relative movement between the support and the gripper means, each gripper has pulling means, again in the form of a solenoid valve-controlled pneumatic piston-and-cylinder arrangement, associated therewith, by which each gripper is moved downwardly relative to the support. Furthermore, said support is also moved upwardly, after the grippers have closed, also by support actuating means in the form of a solenoid valve-controlled pneumatic piston-and-cylinder arrangement.
In addition, the illustrative machine comprises a heel rest by which the end of the shoe remote from the end to be lasted, viz. the heel end, can be supported during the lasting operation, said rest being movable into and out of an operative (shoe heel engaging) position by means of heel rest actuating means again in the form of a solenoid valve-controlled pneumatic piston-and-cylinder arrangement. The heel rest actuating means is caused to operate after the grippers have been closed as aforesaid.
For causing the aforementioned operating elements to operate as aforesaid, the illustrative machine is provided with operator-actuatable means in the form of a foot-operated switch, a first operation of which is effective to cause a central or toe gripper to close and to move downwardly, thus to tension an upper gripped thereby. Release of the foot switch at this stage causes the toe gripper to open and to return upwardly to its initial position, e.g. if the operator is not satisfied with the position of the upper on its last.
With the upper satisfactorily positioned and gripped and tensioned by the toe gripper as aforesaid, further depression of the foot switch causes the remaining grippers to close and move downwardly, the support to move upwardly, and the heel rest to engage the shoe heel end.
In this position the illustrative machine comes to rest. The various operations described so far in relation to the illustrative machine are hereinafter called the "first stage operations". When these first stage operations are complete, the operator can then effect various discretionary operations to adjust the tension in the upper by suitable operator-actuatable means in the form of hand levers.
When the operator is satisfied that the upper is correctly positioned and tensioned, he initiates a further part of the operating cycle of the illustrative machine, either by releasing and again depressing the foot switch (in which case the release of the foot switch can be released at any time following the further depression thereof referred to the above), or merely by releasing the foot switch, according to the setting of a selector switch on a control panel of the machine. The former manner of initiating said further part of the operating cycle is referred to as "normal", and the latter as "high speed".
The illustrative machine comprises wiper means movable from a retracted position to an operative position in which an upper, tensioned over its last as aforesaid, can be held between the wiper means and an insole held against the last bottom. The wiper means comprises an wiper carrier which is movable by wiper carrier actuating means, in the form of a solenoid valve-controlled pneumatic piston-and-cylinder arrangement, in a so-called wiper head. The carrier carries two wiper members mounted for pivotal movement relative to one another and to the carrier, such pivotal movement being effected, by cam means secured on the wiper head, as the wiper carrier moves under the action of the wiper carrier actuating means as aforesaid.
The illustrative machine is a machine for carrying out so-called flat lasting operations, that is operations in which the marginal portions of a forepart are wiped under an insole held against the last bottom as aforesaid (as opposed to a so-called Veldtschoen outflanging operation in which the marginal portions are held against marginal portions of an upper surface of an insole which is of larger area than the last bottom for the purpose). For ensuring that an insole is held securely against the last bottom during movement of the wiper means to its operative position, and to prevent thereby the wipers from entering between the last bottom and the insole, the illustrative machine comprises a presser member movable, by presser member actuating means, again in the form of a solenoid valve-controlled pneumatic piston-and-cylinder arrangement, into and out of an operative, insole-engaging, position, in which an upper insole-engaging surface thereof lies in the plane of the aforementioned support, or substantially so.
In addition, the illustrative machine comprises a toe-engaging member in the form of a toe band which is mounted on the wiper head and is movable, by toe band actuating means again in the form of a solenoid valve-controlled pneumatic piston-and-cylinder arrangement, forwardly and downwardly, whereby to cause it to engage and wipe down the upper and hold it against the last in the region of the feather line at the toe end thereof, two pusher members being provided, one at either side of the last, for urging opposite end portions of the toe band into pressing engagement with the shoe. For moving the pusher members, each has associated therewith pusher member actuating means in the form of a solenoid valve-controlled pneumatic piston-and-cylinder arrangement.
The toe band serves to hold an upper in tensioned condition as the wiper means moves to its operative position, in timed relation with which movement at least some of the grippers are caused to open thus to release the marginal portions of the upper gripped thereby. (The timing of the opening of the grippers in relation to such movement of the wiper means is discuseed in detail hereinafter).
The illustrative machine is adapted for performing cement lasting operations, that is to say the wiped-under marginal portions of the upper are secured to marginal portions of the insole contacted thereby by means of adhesive. More specifically the adhesive used is a so-called hot melt adhesive. The adhesive is applied between the marginal portions of the upper and of the insole prior to the upper marginal portions being wiped under as aforesaid. In the illustrative machine the presser member has formed, in its insole-engaging surface, a channel into which adhesive can be supplied, the arrangement being such that, with the preser member engaging an insole as aforesaid, adhesive supplied to the channel is thus applied to said insole. In the illustrative machine adhesive in rod form is used, the arrangement being such that feeding a portion of rod into a melt chamber of adhesive applying means of the machine is effective to cause molten adhesive to be supplied to said channel. For thus feeding rod adhesive, the illustrative machine comprises feed means in the form of an adjustable stroke solenoid-valve-controlled pneumatic piston-and-cylinder arrangement. Furthermore, melt chamber heater means is provided for heating the melt chamber to a temperature at which the adhesive will melt and be maintained in molten condition.
In addition, the wiper members are each provided with wiper member heater means for heating said members to a temperature appropriate for efficiently effecting a cement lasting operation.
In the operation of the illustrative machine, the movement of the wiper means is arrested in its operative position by a stop member, a switch being at the same time operated by an actuator therefor to cause the presser member actuating means to operate to move the presser member to an out-of-the-way position. Also at the same time, a solenoid valve is operated to admit air under pressure to the "exhaust" side of the piston-and-cylinder arrangement of the wiper carrier actuating means whereby to balance the pressures applied to both side of the piston thereof. The wiper members, which are holding the marginal portions of the upper against the insole, thus assist in holding the insole against the last bottom during the movement away of the presser member, so that any tendency of the adhesive to pull the marginal portions of the insole away from the last bottom is resisted. When the presser member has reached its out-of-the-way position, a further switch is operated to actuate stop member moving means whereby the stop member is removed from obstructing movement of the wiper means. At the same time, the solenoid valve admitting "balancing" air under pressure is de-energised and the movement of the wiper means can thus continue. During such continued movement, any grippers which had not previously been caused to open are caused so to open and release the upper gripped thereby. It is to be noted that none of the grippers is caused at this time to move upwardly to its initial condition, so as not to foul on the under-side of the wiper members.
When the wiper means reaches the full extent of its inwiping movement, bedding pressure is applied to the wiped-under marginal portions of the upper to secure them to the insole. To this end, the illustrative machine comprises bedding pressure applying means, comprising a so-called toe pad, which is moved downwardly into engagement with the toe portion of the shoe upper carried on its last, and a solenoid valve-controlled pneumatic piston-and-cylinder arrangement for so moving the toe pad. At the same time, the support moving means is caused to operate to move the support for the last downwardly out of engagement with the insole. In this condition, the shoe is supported by and inwiped marginal portions of the upper are pressed against, the wiper members.
This condition is maintained for a period determined according to the type of adhesive used and the properties of the upper and insole materials, being sufficient to ensure a proper bond between the upper and insole.
The various operations described, in relation to the illustrative machine, as being performed during the aforementioned further part of the operating cycle of the machine, are hereinafter called "second stage operations".
At the end of the period during which bedding pressure is applied, the various operating elements are sequentially returned to their initial condition, so that the shoe whose forepart is now lasted is released and the illustrative machine is ready for a next operation.
Machines for pulling over and cement toe lasting flat lasted shoes having the various operating elements described above, or common variants thereof, and operating in the manner described above, or in a generally similar manner, are well known and are commercially available. Such commercially available machines also comprises control means for controlling, in a desired sequence, operation of the actuating means for the various operating elements, the pulling means for the grippers, the rod feed means and the bedding pressure applying means (hereinafter referred to collectively as "the various actuating and like means"). Such control means, however, conventionally comprise microswitches actuated sequentially by cam means carried by some moving part of the machine in combination with various operator-actuatable switches. In an alternative control system, the solenoid valves controlling the piston-and-cylinder arrangements and associated microswitches are replaced by trip valves themselves directly actuated by cam means in the same manner as the tripping of the microswitches as aforesaid. In either case, however, dirt and other injurious matter may affect the efficient operation of the switches or trip valves. More recently a so-called sold-state control circuit has been experimented with, but without complicated and expensive safety circuits to counter any possible malfunction of the components of the control circuit; the operator is put at risk in the initial handling of the shoe upper in the vicinity of the wiper members and the grippers.